Sunflower Star

Author: Allie Graff

Common name: Sunflower Star

Scientific name:Pycnopodia helianthoides

Size range: Up to 1 m (about 39 inches) across

Identifying Features

The Sunflower Star is the largest sea star in the world, and is also known as one of the fastest. Even out of water, it comes only a close second to the Sand Star in terms of speed. Its speedy movements are courtesy of the fast-moving tube feet located underneath the sea star’s arms. It can have up to twenty or more arms. The Sunflower Star is usually bright orange or purple in colour.

Habitat

Sunflower Stars are abundantly found on rocky shores, but can also be seen in intertidal zones and in deeper waters where they inhabit the sea floor. It’s also not an uncommon sight to see them clinging to piers with other sea stars.

Prey

Sunflower Stars are very voracious eaters. Given their size, they have to eat substantial amounts of food. And thanks to their flexible skeleton, they can eat almost anything. Sunflower Stars provoke many interesting escape reactions from their prey; sea cucumbers wrestle the star to get away, swimming scallops flap their shells together to flee, and Nuttall Cockles use their foot to vault away from the predator.

Predators

There are only a few animals that prey on Sunflower Stars; the Alaskan King crab (Paralithodes camschaticus) , sea otters (Enhydra lutris) and gulls (Laridae spp.). It is more commonly food shortage that reduces the numbers of adult Sunflower Stars, although filter-feeding organisms feed on them while they are in their larval stages.

Life Cycle

Sunflower Star eggs turn into bilateral swimming larvae, which remain among the plankton for no more than 10 weeks. When they metamorphose on the sea floor, they resemble 5-armed sea stars. Additional arms are added during the course of the juvenile sea star’s life. They have external fertilization and two sexes.

The Bat Star generally has five stubby arms, but has been found with as little as four and as many as nine, which stem out of its wide central disk. These arms are connected by webbing, giving them their bat-like appearance. They come in a wide range of solid and mottled colours including brown, yellow, red, orange, purple, gray, and green. Its ossicles-plates on the surface of the star- are large and distinct, giving the appearance of rough shingles.

Habitat

The Bat Star is found intertidally to 951ft deep off the coasts of Alaska to California in rocky areas covered with algae or surf grass, and among kelp forests, sponges, and bryozoans.

Food

The Bat Star is omnivorous, scavenging on dead or living animals and plants including seaweed, sponges, sea urchins, chitons, barnacles, snails, limpets, sea anemones, and squid eggs. It finds its prey with the help of light sensors on the end of each arm, and consumes its prey by enveloping it with its stomach and secreting digestive juices, creating an ingestible liquid soup. When it is done feeding, it retracts its stomach back into its body. However, it can be difficult for the Bat Star to catch its prey, as the touch of a tube foot or the scent of the star can trigger an escape response.

Life Cycle

A. miniata reproduce through spawning, which is not synchronized between individuals. Sperm and eggs are released into the ocean and carried by the current to different places. Eggs are released from pores where the rays connect to the central disk. They can breed anytime during the year-most commonly from May to July-but need two months for their gonads to build up until they are able to spawn again. Their embryos and larvae are transparent, and these stars can live up to 30 years.

Male Bat Stars have also been seen in mating “fights”, which from the outside looks like an arm wrestle-each star vying to place their arm on the others in a sort of slow motion battle.

Photos by Paige Bodin

Predators

Sea stars do not have many predators in adulthood, though when exposed at low tide, sea gulls and otters will feed on them, oftentimes leaving partially eaten sea stars to regrow their limbs. Snails and nudibranchs are a threat to the much more vulnerable larvae.

The pacific blood star is typically red-orange in colour, but colours may vary from tan to almost purple and is sometimes mottled. The centre disk is very small and the arms can be as long as 8.9 centimetres (3.5 inches). Most Blood Stars have five tapering arms that are nearly cylindrical. Small, dull spines cover their bodies. H. leviuscula moves using hundreds of tiny tube feet with suction cups under their arms.

Habitat

Blood Stars live mostly on the protected sides or under rocks but also in caves and pools. They prefer rocks that carry a lot of sponges and bryozoans. H. leviuscula tend to stay between the low tide line and water 400 metres (1 312 feet) deep. They range along the Pacific coastline from Alaska to Baja California, and the coasts of Mexico and Japan.

Food

H. Leviuscula prey on bacteria and other small particles which they capture in mucus and then bring to their mouth with their ciliated tracts or by applying their stomachs to the surface of the sponges and bryozoans on which they live to eat any particles which might be trapped there. They also are able to absorb dissolved nutrients through their skin.

Predators

Humans and birds are the only threats to the pacific blood star. Humans, of course, do not eat the sea star but rather beach combers are attracted by its vivid colouring and take them home, not realizing that the star’s colour fades when it dies. Luckily the blood star has a surprising ability; they are able to re-grow body parts as long as a portion of the central disk remains unharmed.

Life Cycle

The blood star’s sexes are separate. Small female blood stars brood their eggs while larger females simply leave them in the water. The orange-yellow eggs usually measure about 1.3mm. Once the eggs hatch the young develop as planktonic forms.

Behaviour

H. leviuscula often have a commensalism relationship with the scaleworm Arctonoe vittata. In 2005 students Shannon Greenlaw, Jill Interlichia, and Lyndi Hetterle did a research project on the activity of blood stars. The study was done on 15 blood stars kept in tank outside with a video time-lapse camera recording their movement. Their findings show that blood stars tend to be more active during the day as opposed to night.

Identifying Features: The Armored Sea Cucumber is covered in calcareous plates. The mouth is located on the top front end and is surrounded by bright red oral tentacles. You would not think it’s a sea cucumber because it attaches to rocks while most other sea cucumber move around.

Habitat: The Armored Sea Cucumber occurs from the Gulf of Alaska to Baja California and they live up to 247m under water. The type of areas they prefer to live in are exposed inlets and on clean steep rocks that are free of any kind of debris.

Food: The Armored Sea Cucumber extends its tentacles into the current and catches passing food (usually plankton or krill).

Predators: The main predator for the Armored Sea Cucumber is the sea star. Other predators are parasitic flat worms and also some kinds of snails that can live inside of them. The snails are organisms that crawl all over the sea cucumber and blend into its colour.

Life cycle: Mating occurs during the months of June to August. The mate releases its gametes into the water by waving its tentacles across the genital pore. The eggs develop for 70 days. They then become a little juvenile sea cucumber that are cautious and live under rocks and in algae. It will take them 5 years to become an adult and then they roughly have 3 more years of life.

Identifying Features: California Sea Cucumbers are generally reddish brown in colour but have many colour forms ranging from dark brown to white. All over its long fat body, there are soft, lighter coloured, cone shaped pseudospines that help it move across the ocean floor

Habitat: The California Sea Cucumber lives in inter-tidal zones to 90 meters deep, in both exposed and sheltered areas. They can be found in these shallow waters from the Gulf of Alaska to Baja, California.

Food: The California Sea Cucumber eats tiny scrap particles of decaying matter or detritus, usually abundant in the areas they live. They have two different methods of feeding: direct deposit feeding, and suspension feeding. Direct deposit feeding is when the sea cucumbers drag their tentacles along the ocean floor to pick up food. Suspension feeding is when they use their fine, buccal tentacles to collect particles out of the water.

Predators: The Sunflower Star (Pycnopodia helianthoides) and the otter are both predators of the sea cucumber. As well, some parts of Asia harvest the California Sea Cucumber for the muscles along the inside of the body wall. To protect itself when confronted with extreme danger, the internal organs are ejected out of the anus, distracting predators with the sticky viscera. Also, they use their 5 long muscle bands to wriggle and writhe in order to try to escape from predators.

Life Cycle: When the California Sea Cucumber reaches maturity at approximately 4 years, they develop separate sexes. Some species lay many small eggs that are fertilized in the water by males and turn into larvae, while others produce large, yolk-filled eggs that hatch directly into cucumbers. Young cucumbers are lighter in colour, smaller and thinner, but they have regular sized conical papillae (or ‘spikes’).

Identifying Features: Purple Sea Stars also known as Ochre Sea Stars, come in a range of colours from deep purple to rusty browns depending on their diet. They have five stiff arms and are covered in small, sharp spines. Their upper surface is a layer of rough “skin”, while the bottom is made up of small tube feet, used for movement. Although they have many tube feet, they are slow moving creatures.

Habitat: The Purple Sea Star lives in the Pacific Northwest in the intertidal zone down to approximately 97m (320ft.) in depth. They are commonly found on rocky beaches in the Gulf Islands and along the coast of British Columbian where they hide under rocks for protection when the tide is out.

Food: The Purple Sea Star eats mostly bivalves, and their diet includes mussels, crabs, barnacles, snails, and certain limpets. The Sea Stars form large groups for feeding and eat by using their strong arms to pull apart the shells of their prey and push one of their stomachs into the shell where they then feed from the inside. The Purple Sea Star is a carnivore, much like most other species of sea stars.

Predators: Since the Purple Sea Star is so well equipped for protecting itself, it has few predators once in its adult stage. Mainly, common gulls have been known to feed off of Purple Sea Stars, and other stars are seen as fierce predators, but with its tough outer layer and ability to hold tight to surfaces with its tube feet, it is rarely targeted as prey.

Life Cycle: Male and female sea stars reproduce by spawning. Pairs of gonads in each of their five arms produce and release sperm or eggs into the water through pores in their skin. Chance fertilization then occurs. The young Sea Stars closely resemble the adults, but without such tough skin.